


Sin

by xCake



Category: Captain America (Movies), Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Big Brother / Little Sister, Enhanced Reader, F/M, Incest, PWP, Sex Pollen, Smut
Language: English
Status: Completed
Published: 2019-10-08
Updated: 2019-10-08
Packaged: 2020-11-27 17:57:06
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,112
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20952530
Author URL: https://archiveofourown.org/users/xCake/pseuds/xCake
Summary: You get hit with a healthy dose of sex pollen, and Bucky’s the only one who can help you. There’s just one small problem: he’s your brother.





	Sin

**Author's Note:**

> Hell yeah, I’ve got like 10 requests for this kink in my inbox! Dedicated to all my ladies with the same fucked up big brother kink as me.

Your body was entirely too hot, a stark contrast to the cold weather outside: winter, with two feet of snow on the ground and black ice all over the roads. With the seatbelt resting uncomfortably between your breasts, your bare thighs and back stuck to the leather passenger’s seat as Bucky drove through the blizzard to get you on the Quinjet ASAP.

The mission was a failure.

Whatever intel Hydra still had under wraps, you hadn’t been able to retrieve it. Instead, you’d walked right into a trap. The moment the two of you broke into the warehouse, a bucket of acid spilled from the rafters right down the front of your body – strong enough to melt away your clothing, yet gentle enough not to hurt you. Much.

If you weren’t enhanced, it probably would have killed you. As it was, the acid stung, burned, made your flesh entirely too sensitive to the touch. What’s worse was that it dried within a minute or two, but the chemical reaction only worsened. Even the soft fleece blanket your brother retrieved from the trunk seemed to chafe, but you covered yourself with it anyway.

At least, in the beginning.

Your skin was still flushed wherever the acid melted away any hint of modesty you might have had. You could still almost feel it trickling down your body, that uncomfortable tingling sensation as it dissolved the thick fabric of tac gear -- not to mention your bra and panties. The pleasant burn of it still lingered on your nipples and your clit, and the heady scent of it stuck to you, acidic and cloying and far too sweet.

By the time the two of you reached the Quinjet, you weren’t the only one burning up.

What you could recall was Bucky’s agonizing warmth as he carried you onto the jet; the chill of his metal fingertips as they dug into your bare side, where the blanket must have slipped away; and the smell of him, cedar and spice – so masculine – thta sent a surge of heat straight to your core. 

A fever dream. Unbearable pain laced with the most incredible pleasure.

When he lay you down on the padded table, your fingers caught in his tac vest.

“Bucky,” you whined, squeezing your thighs together. “It hurts.”

“I know,” he murmured, smoothing your hair away from your sweaty forehead with one large hand – flesh, not metal. Hot, too hot.

“Use your—” you panted, back arching off of the table, “your other one._ Fuck_.”

His eyes met yours, steel blue full of conflict and confusion until you pulled his vibranium hand to your forehead. Then your eyes fluttered shut and you let out a soft, shaky breath. While it did nothing to alleviate the ache in between your legs, or all over the rest of your body for that matter, the metal was ice cold and for that, you were thankful.

Not for long, however. Your body heat quickly warmed it right up.

“Tell me what to do,” Bucky pleaded with you. “What should I do?”

“Autopilot,” was all you could manage. Raspy. Desperate.

_Get me back to the lab._

Bucky was gone for no more than a minute or two at most, but to you it felt like an eternity. You barely even noticed when the Quinjet took to the air, too absorbed in the sensations prickling at your bare skin. At some point, you kicked away the blanket – not that you cared. 

All you could feel was the thrum of desire running through your veins. The evidence was smeared in between your bare thighs, white and creamy.

By the time your brother returned, you couldn’t think straight anymore.

“Jesus,” Bucky swore under his breath at the sight that greeted him: his little sister writhing on the table, naked and wanting and his resolve was already about to snap. The too-sweet aroma permeating the air of the Quinjet wasn’t just affecting you, but him, too, especially with his enhanced senses. That wasn’t the only thing he could smell; the tang of your arousal was unmistakable.

“Tell me what to do,” he said again, low and rough. “What do you need?”

Bucky knew what you needed. He just couldn’t give it to you. 

“I don’t know,” you sobbed. “Do something, Bucky, _please_.”

_Couldn’t_ quickly turned to _shouldn’t_, and he swallowed thickly. “I— I can’t—”

You finally cracked your eyes open to peer up at him, only to find that he looked just as wrecked as you felt. His eyes were half-lidded and hazy, pupils blown as he stared at you, naked and on full display in front of him. All forhim.

“Please,” you begged, bringing his flesh hand to the center of your heaving chest.

Bucky’s palm was so hot to the touch against your flushed, hypersensitive skin. You weren’t sure if it was you or him who brought it to your breast, but the way he tweaked your nipple let you know it wasn’t _entirely_ you.

Even his protest was weak. “You… You don’t know what you’re asking for, sweetheart.”

The pet name rolled off of his tongue so easily, despite the fact that it wasn’t something he’d ever called you. It made you shiver. You peered up at him through your lashes, worrying your lower lip in between your teeth as you pulled his hand lower – trailing it down your stomach to the top of your curls.

“Please,” you repeated, breathier this time. 

His resolve shattered to pieces.

The way Bucky kissed you was rough and desperate, and although the passion behind it may have been artificial, his skill certainly wasn’t. You knew what a playboy he used to be and he definitely didn’t disappoint. His tongue just barely traced the seam of your lips before you opened your mouth to him, letting him dominate you in every sinful way.

It wasn’t right.

It didn’t matter.

Your body was on fire and he was the only one who could put out the flame. 

Bucky’s fingers slid between your slick folds with ease, and you moaned into the kiss at the intimate contact. Even you could hear how wet you were.

That was when his lips left yours to suck and bite at the tender flesh of your neck, a momentary distraction before he buried two thick fingers deep inside of you – and when he curled them right against your sweet spot, your eyes rolled back.

A string of curses followed when he started to fuck you with his fingers, and he wasn’t gentle, no – the pace he set was rough and punishing, focusing right on your g-spot with every pass, with every mark he left on your neck and breasts. The wet, sloppy sounds echoing off the walls of the Quinjet might have been embarrassing if you weren’t so blissed out of your mind already. Instead the vulgarity of it all just brought you higher.

Breathy whimpers and gasps of his name escaped your throat, along with pleas for him not to stop as the pressure further built, until tears were streaming down your face – blissful tears and uncontrollable sobs because it felt too fucking good, _god_, you needed this, needed _him_—

Mindlessly, your hands fumbled with the coarse fabric of his tac shirt, where you felt his bicep flex beneath the material as he worked downright fucking magic on your body. “God, _Bucky_—”

“Come on, sweetheart,” he whispered, and then he kissed you again – messy, all tongues and teeth. You could feel yourself getting closer and closer until he finally murmured against your lips, “Come for me.”

The rough timbre of his voice coupled with everything else was just enough to send you over the edge, and you came harder than you ever had before, thighs shaking at the intensity. Bucky swallowed every single one of your moans – not that being quiet was a priority.

You felt lightheaded as he gently withdrew his hand from your slick heat. The expression on his face was unlike anything you’d ever seen: cheeks flushed, eyes dark with desire as he stared in awe at the mess you’d made. Your juices were all over his fingers, sticky sweet and he slowly, teasingly licked them away.

Seeing your brother do something like _that _stoked the raging fire within you, and in that moment you knew that the two of you were going straight to hell. Why prolong the inevitable?

Hands trembling, you reached for his belt. He didn’t even try to stop you. Instead, he fisted your hair and used his tight grip to pull your mouth to his.

In seconds, you had his belt unbuckled and his pants down around his ankles. Bucky broke the kiss just long enough to take the rest of his clothes off – tac vest and shirt, mostly – and then he was nestled in between your legs atop the padded table.

You’d never seen his cock before, but damn if it didn’t make your mouth water. 

When your fingers wrapped around his throbbing length, he let out a shaky breath and rested his forehead on your shoulder. When he spoke, he sounded just as desperate as you felt, “You’ve gotta tell me to stop.”

“I don’t want to stop,” you admitted.

The tip of his cock brushed against your soaked core, then, and both of you shivered at the feeling. The fingers of his vibranium hand dug into the soft flesh of your hip – holding you steady for what he was about to do.

“Neither do I,” he growled, and then he slammed his hips forward so that he was fully seated within you in one single thrust.

You let out a strangled cry at the feeling, at the stretch – a pleasant burn that felt way too good for what it was, for what the two of you were.

This wasn’t right.

You didn’t care.

You rolled your hips against him in a plea – or maybe it was an order.

“So needy,” he breathed against the sweat-slickened skin of your throat, sucking another bruise there to add to the collection. “Always so fucking needy.”

You were. He was speaking from experience – his bratty little sister.

The thought of it made your walls clench around him, and he groaned. “_Fuck_, sweetheart. You like that?”

The sound that escaped you was something in the affirmative, but you couldn’t really verbalize it properly. He felt too good.

“Jesus Christ, doll, you’re squeezing me like a vice,” Bucky rasped, laving his tongue over your collarbone as he thrust into you. His grip was sure to leave bruises, but you didn’t care about that, either.

All you cared about was that you were being fucked right out of your mind – by your _brother_.

That was when Bucky hiked your leg up higher around his waist with his free hand. The new angle allowed him even deeper inside, and you threw your head back, moaning as the tip of his cock brushed against your cervix.

“You’re mine,” he panted against your neck.

Your heart raced at his possessive words.

“I’m yours,” you whimpered in response, burying your fingers in his hair to drag him down for another kiss. It was just as messy as his thrusts were starting to become, frantic and harsh as you both got closer to the edge.

Bucky only broke away to look at you, and though his eyes were dark, so up close you could just make out the blue of his iris. There was something intimate about the way he held your gaze, and in an instant you were too far gone to hold back, gasping, “Fill me up.”

You wanted his cum. You _needed_ it.

His eyes widened just a little, before his hips stuttered and then he slammed into you as deep as he could go, groaning your name. The second you felt his cock throb inside of you, your orgasm crashed down upon you like a sheet of ice – your legs squeezing around his waist, fingers tightening in his hair as he spilled inside of you. Your walls milked him dry, squeezing with each pulse of his cum until there was nothing left.

As you and Bucky regained your breath, he slowly pulled out of you, gingerly, almost – like he didn’t want to hurt you. Bruises were already starting to form on your hips, and your neck and chest were covered in marks he’d left – marks stemming from a passion that should never have existed.

They’d disappear soon enough, but _nothing _would be soon enough.

The fire was gone.

By the time you got back to the compound, the only evidence of your sin was his cum dripping down your thighs.


End file.
